With rapid development and continuous innovation in the lighting industry, and the growing importance of energy savings and environmental protection, LED lighting rapidly developed as an important lighting technology. However, the luminance of LED lighting (associated with the parameter of luminance intensity) is in direct proportion with the current and forward voltage drop of the LED, and is also varied with temperature. Therefore, a constant current generator may be necessary to drive the LED. Conventional constant current typically use an optical coupler, voltage reference, and sensing circuit as part of an output regulating circuit.
However, such conventional constant current generators have several drawbacks. For example, optical coupler may deteriorate over time, and the transfer ratio of current may decay, resulting in a disadvantageous effect on the stability and life for some applications. Also, increased space may be occupied, resulting in increased costs due to the large number of devices, which also may result in relatively low reliability. Further, the sensing circuit usage may result in increased power loss and lower efficiency. Therefore, conventional LED drivers may not meet the needs of smaller size, higher efficiency, and increased energy savings.